1. Field of the Invention
This invention relates to electronic enclosures in general and more particularly to an electronic enclosure for high frequency microwave circuits that use coaxial connectors.
2. Description of Related Art
Referring to FIGS. 1-3, an electronic enclosure 20 of the prior art is shown. Enclosure 20 has a housing 22, top cover 24, bottom cover 26 and connectors 40. Housing 22 has four side walls 32 that surround a cavity 31. Housing 22 has four screw holes 33. The side walls 32 have a female threaded aperture 34 that extends entirely through the thickness of wall 32. The connectors 40 have a pair of male threaded ends 42, 43, a central nut portion 44, a pin 46 and an insulator 48. The connectors can be a conventional coaxial connector such as an SMA connector. The connector ends 43 mate with the threads of aperture 34 and are tightened in place using a wrench on nut portion 44. An electronic circuit assembly 52 such as a printed circuit board is located in cavity 31. Covers 24 and 26 have holes 25 for accepting a fastener such as a screw 50.
A typical assembly sequence of the prior art enclosure 20 is as follows:
1. A locking compound is placed on threads 43.
2. Connector 40 is screwed into apertures 34 of housing 22 and tightened.
3. The housing is placed into an oven to cure the locking compound at an elevated temperature.
4. Components are installed on electronic circuit assembly 52.
5. Circuit assembly 52 is placed into housing 22.
6. Pins 46 are soldered to pads on the circuit assembly 52.
7. Connector 40 is soldered to ground on circuit assembly 52.
8. Top cover 24 is then placed over housing 22 and fastened in place with screws 50.
9. Bottom cover 26 is then placed over housing 22 and fastened in place with screws 50.
The torque required to mount the connectors is an important parameter. The torque has to be high enough to prevent the SMA connector from detaching during the normal mating and un-mating process of the female end of the SMA connector (not shown). Normally, an organic locking compound such as Loctite is used on the threads 43 to obtain a high unscrewing torque and to keep connector 40 in place. Unfortunately, in high frequency applications, the locking compound may create continuity problems and degrade the electrical performance of the housing. Using screws to attach the connector to the housing is time consuming, uses manual labor and is expensive. In addition such a process is difficult to automate. Another problem with the current electronic enclosures such as housing 22 is that the threads in aperture 34 have to be precisely machined which adds to the cost of the housing. A further problem of enclosure 20 is that the individual component count is high which results in a large number of process steps during assembly.
While various electronic enclosures have been previously been used, they have suffered from having a high part count that is expensive to assemble and from continuity problems due to the use of locking compounds.
A current unmet need exists for an improved electronic enclosure that is low in cost, easy to assemble and high in reliability.
It is a feature of the invention to provide a package for containing an electronic circuit assembly that is low in cost and requires fewer manufacturing steps.
Another feature of the invention is to provide a package for containing an electronic circuit assembly. The package includes a housing having a bottom surface and a plurality of walls extending upwardly from the bottom surface. The walls and the bottom surface define a cavity in the housing. The cavity is adapted to hold the electronic circuit assembly. A post extends outwardly from one of the walls. The post is integrally formed with the housing. The post has a first end and a second end. The first end is connected to the wall. A threaded annular sleeve portion is located at the second end of the post. The threaded annular sleeve portion is adapted to receive a female connector portion. A bore passes through the post and the wall. The bore is adapted to receive a terminal. A cover is located over the cavity and is attached to the housing.